Numerous human sperm preservative media are in market. Many world leading companies are working to manufacture, upgrade and market human sperm preservative medium. But till date none of them worked to find or specify the ideal human sperm preservative medium and method. With this discussion we will simply try to enumerate the demerit of present human sperm preservative media and method. As well as we will also try our best to characterize ideal human sperm preservative medium and method.
Currently available sperm preservative medium is a mixture of many inorganic and some organic salts. It also contain sperm cell wall permeating and non permeating chemical substance to protect the sperm from damaging cryo-injury. The osmolarity (salt concentration) of human sperm preservative media is higher than any body fluid. Other than above salt sperm preservative medium also contain human serum albumin. Which complete composition is still not clear. Method of human sperm preservation is still more or less conventional. New equipment ( Programmable freezer, etc) has been tried to implement. At this point I would like to make it clear that temperature at vapor stage of liquid nitrogen can be reduced at any rate even manually. This is our practical experience that use of programmable freezer is only a way to sell this equipment. Certainly it is having its value in research. Otherwise it is of no use and simply increase the operational cost.
Demerits of conventional human sperm preservative compound and method.
- Its composition is not uniform – every manufacturer is making some variation and claiming it best one.
- All sperm preservative media contain human serum albumin.
- Exact composition of human serum albumin is not clear. There is batch to batch and collection to collection variation in human serum albumin.
- Human serum albumin is being obtained from another person. Therefore there is always a risk to transmit disease. Although human serum albumin supplier claim that they take all possible measures to supply disease free human serum albumin. But somewhere errors are unavoidable.
- Present science is not capable to detect emerging and undiagnosed virus and micro-organism. Therefore transmission of emerging and undiagnosed virus and micro-organism can not be prevented.
- Certain Disease like CJD (Creutzfeldt–Jakob disease) cannot be diagnosed in early stage and can be transmitted.
- Human serum albumin may also have some endotoxins.
- Method of human sperm preservation is getting costlier day by day. This is because of creating necessity of programmable freezer . Which is not a fact.
- Every sperm preservation media manufacturer are advocating their own method to freeze human sperm.
- Method of sperm preservation by freezing in liquid nitrogen is still cumbersome and time taking.
- Thawing (bringing the sperm to normal temperature) protocol is not universal.
Required characteristics of ideal human sperm preservative medium and method.
In our day to day work, we noted that following measures should improve the preservation of Human sperm . As well as these measures will make the human sperm preservation easy, practical and safe.
- Human sperm preservative medium should not contain human serum albumin or any protein which comes from any living creature.
- Preservative compound must be 100 % chemically defined.
- Freezing of human sperm should not require any costly equipment.
- The method should be easy, acceptable and cost effective.
- The composition of human sperm preservative medium should be simple and easy enough. How to prepare it anywhere should be documented. Which will drastically reduce the cost of human sperm preservation.
- The time required should be minimum to perform preservation of human sperm.
- Vitrification seems a way to make human sperm preservation easy, cost effective and practical.
- Thawing should be done at a temperature of 32 degree C to 34 degree C. This is because development, maturation and storage of sperm is taking place at this temperature only.
- Preserved sperm should be quarantined properly to prevent disease transmission from sperm donor side.